At present, with continuous popularization and improvement of automation level of manufacturing enterprises, manual carrying has been gradually substituted with robot carrying for the carrying operation in the hub production process, and the transfer operation between a ground chain and another ground chain, a roller bed and the like in a coating line of a hub has been increasingly widely applied. The robot transfers the hub generally in such a manner that the clamping jaw clamps the rim. However, the conventional clamping jaw has two shortages in the clamping operation: firstly, in order to prolong the service life of the clamping jaw, the clamping fingers of the clamping jaw are generally made of a hard wear-resistant material, causing certain damage to the surface coating of the hub; and secondly, when the wear extents of the clamping fingers on two sides of the clamping jaw are inconsistent, the hub may be clamped obliquely and even the hub brace is bent by lateral force.